We have observed one-particle, inelastic, polarized light scattering from low-lying excitons and magnons in single-crystal cobalt fluoride (Co${\mathrm{F}}_2$) at 2°K. Because of the orbital nature of these excitations, the cross sections (${10}^{-33\mathrm{}}$-${10}^{-32\mathrm{}}$ ${\mathrm{cm}}^2$/sr) are much larger than for one-magnon scattering in the other case, which has been measured (Fe${\mathrm{F}}_2$, ∼${10}^{-35\mathrm{}}$ ${\mathrm{cm}}^2$/sr). Our measured cross sections are in good agreement with a recent calculation by Ishikawa and Moriya.

The anomalous shapes of the angular distributions of tritons from the $0^{+}$→$0^{+}$ ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-induced charge-exchange transitions to antianalog states of ${}_{}{}^{64,66}{}_{}{}^{}\mathrm{Ga}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{K}$ can be understood on the basis of the structural relation between analog and antianalog states, together with the assumption of a pure charge-exchange (i.e., no knockout) mechanism.

The fore-aft asymmetry of the angular distribution for the reaction $d(\alpha ,t){}_{}{}^3{}_{}{}^{}\mathrm{He}$ at 82 MeV is compared with the result of a simple distorted-wave Born-approximation calculation. We find that if Coulomb effects are included, the general features of the asymmetry can be reproduced.

It is argued that the differential rates of production of neutral di-pions in a reaction of the type $X\to Y+\left(\pi \pi \right)$ have the form $\frac{d{\sigma }_{+-}}{k^2\mathrm{dk}}=A+Bk+O\left(k^2\right)$, $\frac{d{\sigma }_{00}}{k^2\mathrm{dk}}=C-Bk+O\left(k^2\right)$ for small values of $k$, the pion relative momentum in the di-pion rest frame. Determination of the coefficients $A$, $B$, and $C$ would yield the bound $|{\alpha }_2-{\alpha }_0|>~\frac{3\left|B\right|\mathrm{}}{2{\mathrm{}\left(\mathrm{AC}\right)\mathrm{}}^{\frac{1}{2}}}$, where $a_I$ is the $\pi \pi$ scattering length for isospin $I$.

Rigorous upper and lower bounds are prescribed in the form of approximate quadratures for a variety of oscillator-strength sums. The required integration points and weights are determined from continued-fraction approximants and linear programming techniques, employing oscillator-strength moments as inputs to the method. Illustrative bounds are provided in the cases of atomic hydrogen, helium, and neon, for odd-integer sums and for the mean energies associated with stopping, straggling, excitation, and the Lamb shift.

It is proposed to use the saturated value of the radiation pressure force on neutral atoms to produce a constant central force field to deflect atoms in circular orbits and make a high-resolution velocity analyzer. This is useful for studying the interaction of atoms with high-intensity monochromatic light, and to separate, velocity analyze, or trap neutral atoms of specific isotopic species or hyperfine level.

The spin polarization of photoelectrons emitted by unpolarized cesium atoms exposed to circularly polarized light has been measured at wavelengths between 2300 and 3200 Å. At certain wavelengths 100% polarization has been obtained. Slight deviations from theory have been observed. Irradiation of a broad mercury spectrum resulted in (81± 3)% polarization with a current of 0.3×${10}^{-10\mathrm{}}$ A.

The influence of electric dc fields on spontaneously aligned doped films of the nematic liquid crystal anisylidene-$p-n$-butylaniline was investigated. Prior to the application of the field films were uniaxial with the optic axis normal to the substrate; under the influence of a field applied perpendicular to the optic axis films became biaxial. The magnitude of the induced retardation was measured as a function of field strength, and found to increase linearly with $E^2$.

The translational self-diffusion coefficients of the ${\mathrm{H}}_2$O molecules in the water channels of both hexagonal and lamellar lyotropic liquid crystals have been measured by the variable field-gradient proton spin-echo method, and the temperature dependence of the ordering of ${\mathrm{D}}_2$O and ${\mathrm{H}}_2$O molecules was studied by quadrupole perturbed deuteron NMR and proton spin-lattice relaxation measurements.

We have shown experimentally that a magnetic field is created by the electrons of a plasma subjected to high-power pulses of circularly polarized microwaves. The experimental results confirm the predictions concerning this phenomenon, known as the inverse Faraday effect.

We show, with a single-mode $Q$-switched laser and a single-mode mode-locked laser, that the observed small-scale filaments are actually the tracks of moving foci, but under suitable conditions, light can be trapped over an appreciable distance in these tracks. The results are in rough agreement with theoretical prediction.

The mechanism of filament formation, consisting in resonant enhancement of elastic lattice vibrations, is responsible for thermal periodicity both of number of filaments and of intensity of stimulated Raman scattering. Mechanical tuning and some test experiments are discussed.

The range in energy over which Bragg reflections are excited in low-energy electron diffraction is anomalously large when compared with the expected values of the energy band gaps. It is concluded that elastic scattering is restricted to within 2-4 atom layers of the surface in all materials studied, preventing a direct comparison between low-energy electron-diffraction data and band structure.

The half-lives of the lowest $6^{+}$ states in ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$, ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$, and ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}$ have been measured to be 0.41±0.02, 1.24±0.04, and 5.52±0.15 nsec, respectively. The deduced polarization charges $\delta e_{\mathrm{eff}}$ are around $0.65e$ both for the $f_{\frac{7}{2}}$ proton and neutron.

Resonating-group calculations predict a backward-peaked, exchange resonance in the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ + ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ elastic-scattering cross section. We have measured the energy dependence of the elastic-scattering differential cross section at 173.2° (c.m.) and have observed a resonance structure which has many of the predicted characteristics.

The decay asymmetries resulting from the residual polarization of negative muons were measured in the components of the ground-state hyperfine doublet of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$, and ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ muonic atoms. The results show a characteristic consequence of the muonmucleus magnetic dipole coupling during the muonic cascade.

The total cross sections for the reactions ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$[0.871])${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$[0.871]${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ have been measured at energies well below the Coulomb barrier. The data have been fitted with the Buttle and Goldfarb formulation of distorted-wave Born-approximation theory and spectroscopic factors extracted.

The mean lives of the second and third excited states in ${}_{}{}^{40}{}_{}{}^{}\mathrm{K}$ are (0.65 ± 0.15) × ${10}^{-12\mathrm{}}$ and (1.6 ± 0.3) × ${10}^{-12\mathrm{}}$ sec, respectively. The relative speeds of the three $M1\mathrm{}$ transitions between the four lowest states are incompatible with these states being pure ${\left(\pi d_{\frac{3}{2}}\right)}^{-1\mathrm{}}\times \left(\nu f_{\frac{7}{2}}\right)$-even if effective moments are used; neither small components of the most likely shell-model impurities nor any possible $E2\mathrm{}$ admixture improves the fit. A similar situation appears to hold in ${}_{}{}^{38}{}_{}{}^{}\mathrm{Cl}$.

It is proven that in an orthogonal quadrupole system a beam entering parallel to the optic axis is necessarily brought to at least one point or line focus.

The neutral branching ratios of the $\eta$ meson have been determined from the energy spectrum of single $\gamma$ rays in the $\eta$ center of mass. The sample of 7200 events after background subtraction yields $\frac{(\eta \to \gamma \gamma )}{(\eta \to \mathrm{neutrals})}=(53.5\mathrm{}\pm 1.8)\%$, $\frac{(\eta \to {\pi }^0\gamma \gamma )}{(\eta \to \mathrm{neutrals})}=(2.6\mathrm{}\pm 1.9)\%$, and $\frac{(\eta \to 3{\pi }^0)}{(\eta \to \mathrm{neutrals})}=(43.9\mathrm{}\pm 2.4)\%$ under the assumption that no other neutral decay modes contribute. The quoted errors include an estimate of possible systematic effects.